Like all alkali metals, lithium is highly flammable - making lithium-ion batteries a fire risk. The batteries are often used in cell phones and laptops because of their small size and light weight as compared to other batteries. Lately, they’ve been heavily utilized in electric and hybrid vehicles, such as in Tesla’s Powerpack for its fleet of self-driving cars.
However, researchers might have found a solution to this problem, developing lithium-ion batteries that will not catch fire or explode.
Additionally, these batteries also produce enough energy to power household electronics and will never ignite, despite constant interference by the researchers.
In their study, published in the journal Joule, co-author Kang Xu, from the US Army Research Laboratory (ARL) elaborated on their process, “In the past, if you wanted high energy, you would choose a non-aqueous lithium-ion battery, but you would have to compromise on safety. If you preferred safety, you could use an aqueous battery such as nickel/metal hydride, but you would have to settle for lower energy, now we are showing that you can simultaneously have access to both high energy and high safety."
The same team developed a similar 3V battery with an aqueous electrolyte but were prevented from reaching the desired voltage by the “cathodic challenge,” when one end of the battery, made from either graphite or lithium metal, is degraded by the aqueous electrolyte.
To combat this, co-author, University of Maryland assistant research scientist Chongyin Yang created a gel polymer electrolyte coating that can coat the graphite or lithium anode.
The hydrophobic coating expels water molecules from the electrode surface, and upon the first charge, the coating then decomposes to form a layer called an “interphase.” This interphase protects the anode from unwanted chemical reactions and allowed the scientists to push voltage up to 4.0, making it perfect for devices such as a laptop computer.
“The key innovation here is making the right gel that can block water contact with the anode so that the water doesn’t decompose and can also form the right interphase to support high battery performance,” said co-senior author Chunsheng Wang, Professor of Chemical & Biomolecular Engineering at the University of Maryland’s A. James Clark School of Engineering.
This isn’t the first attempt at a new incarnation of lithium batteries, Berkley, CA startup Seeo, Inc developed lithium ion cells that they claimed would be safer, longer-lasting and cheaper than the current batteries on the market in 2009. Seeo’s batteries used thin films of polymer as the electrolyte and high-energy-density, light-weight electrodes. Now the patented polymer is called DryLyte which could be used in electric vehicles in as little as three to five years.
The same amount of time that the team at the University of Maryland have allotted for bringing their 4V technology to the commercial market.
Seeo claims they can achieve a cycle life of 1000 with a less than 5 percent capacity loss, while the University of Maryland stated that their aim is a bit less ambitious. “Right now, we are talking about 50-100 cycles, but to compare with organic electrolyte batteries, we want to get to 500 or more,” Wang said.
Let the battery games begin.